Electrolytic rectifier.



- R. n. MERSHON.

ELECTROLYTIC RECTIFIER.

APPLICATION FILED JAN-23.1912.

, Patented Feb. 15,1916.

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a. u. MERSHON. ELECTROLYTIC RECTIFIER.

APPLICATION FILED JAN 23.1912.

1,171,969. Pate nted Feb. 15,1916.

2 SHEETS-SHEET 2- THE COLUMBIA PLn oGRAP" c0., WASHINGTON, D. c.

I ternally operated power device, but any such,

RALPH D. .MER SHON, OF NEW YORK, N., Y.

ELECTROLYTIC RECTIFIER.

Specification of Letters Patent.

Patented Feb. 15, 1916.

Application filed-Tannery 28, 1912. Serial No. 672,898.

To all whom it may concern:

Be it known that I, lianrir D. MnnsnoN, a citizen of the United States, residin at New York, in the county and Stateof ew York, have invented certain new and useful Improvements in Electrolytic Rectifiers, of which the following is a full, clear, and exact description.

It is well known that while the efficiency of theelcct'rolytic, rectifier in its present commercial form may, under some conditions. be fairly high, it diminishes very materially if the device is operated continu ously for any considerable length of time. Thisdrop ,or diminutionis apparently attributableto two principal causes-the increase in thetemperature of the rectifierand its electrolyte, and the accumulation of bubbles of gas on the electrodes,particularly on the filming electrode. .The first of these contributing ca uses,-tln1t of increased temperature-mav be, to a large extent, overcome by the provision of a-radiatingsurface 0f sufficient extent, and inpractice-this course is generally. followed. Butas the eificacy of any given radiatinggsurface, dependslargely upon the'completeness and rapidity of circulation of the electrolyte in the containing vessels, the usual means for promotln c1rculation, by such-,design of the vessef that itivill-be effected-by convection due to the.

heatgenerated in .the elcctrolyte,have notproved adequate, heretofore, to obviate this objection and secure. the desired result. course, the circulation could obviously be increased to any desired degree by the employment of some form of pump or other exauxihary apparatus is manifestly objectionable, being more or less cumbersome, ex

pensive and uneconomicalr 1' The, invention which forms thdstibject of my presentv application affords, incidentally to its main purpose, a simple and efi'ectiye means for/ promotingl a thorough; and rapid circulation of thee ectrolyte, without resorting to the;n se of.eany auxiliary devices. or. ,the1 apphcation, of external, sources of power. for; the s0le,p1 1rposeiof securing circulationr. I have found from investigations-of the matter what ,has not been generally-recognized,.thut th e'bubblesladhering to the filming electrodes are largely responsible for the decrease in the efliciency of the rectifiers attendantupon continued'use. In the case of those commercial forms of this apparatus, which evidence an apparent recognition, on the part of the manufacturers, of this source of trouble, the precautions for the removal or elimination of these bubbles have been limited to efforts to direct the convection currents in the electrolyte so as-to sweep the bubbles off from the filming electrodes. This plan, while partly effective, falls far short of remedying the difliculty, as a great many minute bubbles adhere so firmly to the electrodes as to resist dislodgment by such convection currents as it isfeasible to obtain. This may be demonstrated by plun ing a p1ece of metal, especially if its suri iice be slightly rough, into a glass of clear water. The bubbles which form on and adhere to the surface of the metal will not be displaced byeven a comparatively violent stirring movementof the metal in the water, but if-the metal'be raised out of the water, even though it be.immediately returned, it will be 'foundthat a large part if not all of the bubbles have disappeared; With the object of utilizin this action. in electrolytic valves and recti iers, in which II have found that-it-occurs in the case of filmingelectrodes, I have devised the plan of displacing the electrolyte from the containing. vessel so as to expose' momentarily the electrode or electrodes and then permit its return. To accomplish this I place the filming electrode in aclosed chamber,=jexpel the electrolyte from such chamber by the action of air or gas under pressure and then liberate the ody of confined air or gas to permit the return of the electrolyte. The. compressed air orgas may be obtained from any source. but as an external source is not always available I;;propose to utilize the. gas generated byelectr'olytic action to effect a periodic displacement of theelectrolyte and consequent exposure of the electrode or electrodes, and incidentally to promote such circulation of the electrolyte as greatly assists in dislodging the bubbles as they form.

The-specific embodiment ofthe invention or improvement is illustrated in the accompanying drawings in which- Ei ures 1, 2, 3,.4'and 5 are sectional-views of single electric valves illustrating the principle and various details and modifica- C is'expelled andthe gasconfined in= the-bell tions of the improvement, and Figs. 6 and 7 similar v ews of electrolyt c rectifiers illustrating the application. of the improvement located inside an air ti ht invertedbell jar B of metal forming tlie'non-filming electrode, although, of course,-.the bell ma .be of non-conducting ma'terial'and a nonilmin electrode either without or within the bell employed, preferably the latter, as some bubbles are set freef'fromf'the no'n-filming electrode which assist those'from the filming electrode in etlectin the operations described below. A tube b of small diameter and having one end bent back upon itself extends through an air-tight connection in the top of the bell'B and the parts namedare suitably supported in a containin vessel 1) partly filled with an electrolyte. l 1e conductor leading from electrode A is insulated from the bell B and the electrolyte and the tube C'maybe of metal in which case it may serve as a' terminal for the nonfilming electrode.

The action of the device may be best ex-" plained by a. descriptionof one cycle of operation.

Assuming that the containing vessel-dis filled to the normal level 'with electrolyte and the filming electrode properly formed, the bell and the small benttube 0' will be filled with the electrolyte up tothe level of the main body; in the vessel D. If now the terminals of a source-of alternatingcurrenthe attached, one-directly to one electrode and the other to the-opposite electrode through the' load to which the electric valve is to supply unidirectional current, bubblesfof gaswilbibe formed at-th'e surface ofboth, but mainly at that of the-filming electrode; The greater part of these gas bubbles will be disengaged -by their'own buoyancy and rise tothe topof the bell displacing the electrolyte, 'but' many'will rerna'in' clin ing to the electrodes.'--This" displacement of the' electrolyte will-expose 'more-and more of the surface of thefilming electrode permitting it to free itself of the adhering-bubbles, and this action will continue until, by the-pressure of the gasuthe electrolyte in the tube B is allowed to-escape-. It will bejunderstood that as the level of the liquid'is forced down in the bell, it'-is";also forced down theshort leg of the bent -tube C,anjd the long legof-the same. As soon asfthe has thus been forced around the bend of the tuhe the head of liquid in the tlong leg no l'onger'incrcasesas theli'quid moyes,"and thereforeany increase ofi'ipressure' in the hell. will amt all the liouidjin the tnbe 0 out into the open vessel, thus permitting the gas in the bell to escape and the electrolyte to again rise in the bell to the level of the .end of the short leg of the tube, at which point the electrolyte enters the tube and prevents a further escape of gas. This action ,willbe repeated with cyclic regularity.

-It is evident that the distance to which the electrolyte will be forced down in the bell B will depend upon the length of the short leg of the U-tube C, or upon the total length of the column of electrolyte in the long leg of saidtube'when all of the electrolyte has passed around the bend in the tube or in general upon the particular configuration of the tube which determines the point at which an increased head or height of column of liquid in the tube is no longer produced by a movement of the liquid in the electrode chamber or tube. The device should, therefore, be so arranged that the tube C will discharge before the filming electrode has been entirely exposed, so that there will he still a portion of the electrode immersed to form bubbles and therefore increase the pressure in the bell.

' In order to obtain a uniform rate, or, if desired, a varying rate of movement of the surface of the electrolyte with respect to the electrode, the's'hap e of the bell B may be modified, as for example as shown in Fig. 2, whereby contracting. the lower portions of the bell the rate "of movement will be more nearly uniform, since the volume of gas generated 'is greatest when the electrode is fully immersedl'in the electrolyte.

-In an apparatus organized and constructed as ab'ove'described, it'is evident that the bubbles'will be cleared ofi' periodically from the greater part of the filming electrode, by the withdrawal of the electrolyte therefrom.

The bubbles from its lower end which is not exposed will be cleared off by the violent inrush of electrolyte which-follows the discharge of the tube (3. It is also ap arent.

that this'periodic movement of theelectrolyte will produce in the same a much more complete and rapid circulation than could he -produced by convection currents alone.

From the nature of'the apparatus and its operation thus described, it will be seen that 'the current passing through the valve will be periodically diminished because of the reductionof the active area, of filming electrode incontact with the electrolyte. Tozovercomethis objection theplan may be resorted to which is illustrated in Fig. 3. in which there are two electrodes A andA', the 'latter-of'whi'ch is covered'by the electrolyte at the same-rate that the first is exposed, so that the aggregate areaof filming electrode in contact with-"the electrolyte is constant. In order that this relationmay be maintained the surface of the electrolyte outside the'b ell B must be caused to rise at the Same rate that'the level sinksin the bell, for which purpose the upper portion of the containing vessel is constricted as shown in Fig. 3. A similar result will be secured by making the upper filming electrode shorter and thicker than the other as shown in Fig. 4. In this latter figure is shown also an additional feature providing for a more definite and constantly directed circulation of the electrolyte. In this case the bottom of the bell B is closed, and provided with two mechanical valves F and G, opening in opposite directions. There is also arranged across the containing vessel D a septum H which divides the space outside the bell and up to the top of the latter into two compartments each containing one of the valves above mentioned. It results from this that the electrolyte is always forced out of the bell on one side of the septum and forced into it on the other side. A similarly definite and directed circulation may be socured by the modification shown in Fig. 5, which obviates the use of mechanical valves. In this device the bottom of the bell B opens into one of the two longitudinal compartments of the vessel D, formed by a septum H, while the lower end of the bell has a number of openings K made small or tortuous so as to resist a rapid flow of liquid. By the generation of gas under the bell the hot electrolyte is'slowly forced downward and flows out through the openings K into one of the compartments formed by the septum, but when by the escape of gas through the tube C, there is a rapid inrush of liquid to refill the hell, it enters from the other compartment through the open bottom of the bell. Thus the warm electrolyte constantly rises on one side of the septum, and the cool descends on the other.

In the figures above described the illustrations have been confined to single valves which rectify only half of each alternating current wave, but the improvements are also applicable to com lete rectifiers for rectifying both halves o the wave, and such embodiments of the invention are shown in the remainin figures, Fig. 6 being designed more particu arly to illustrate the principle. In this figure there are two containin vessels L and M, the former and upper eing open, the latter closed air tight. The two vessels are connected by a pipe N through which the liquid is transferred from one to the other and which is formed or connected with a coolin coil 0. intermediate to the two vessels. A -tube C similar to that heretofore described connects the two vessels, and in other respects the arrangement is the same as that previously set forth, except that two filming electrodes A, A, are used,

in each vessel, and a non-filming electrode P of iron or lead. The electrical connections usual for such devices are shown in this figure, but being well understood are not described in detail.

It is evident from the foregoing descripticn of operation that the electrolyte will bx forced from the lower into the upper ves- '1 thus periodically uncovering the elccllr'tlc; in the former, and then returned from the upper to the lower vessel as soon as the gas escapes from the latter through the tube t.

In Fig. 7 is shown a construction by which the expulsive circulation is caused to maintain the same direction of movemrnt as that incident to that due to convection. The nonfilming electrodes P in this case are in tho form of cylinders with numerous perforations through which convective circulation can take place at any height of liquid. pipe R with a single opening concentric with the cylindrical electrode in the upper vessel extends from the bottom of said vessel into the lower part of the lower vessel where it is provided with two or more orifices surrounding the cylindrical electrode P therein. Similarly, a pipe S with openings surrounding the cylinder 1 in the upper vessel leads by a single orifice to the center of the lower vessel. The pipes R and S contain ball check valves T and V, the former permitting an upward and the latter a downward flow of liquid only. In other respects than those noted the construction of the device is or may be the same as that illustrated in Fig. (3. and its operation will be understood without further explanation.

It is apparent from such modifications of the invention as I hereinbefore described. that many others are permissible, and that the improvement is not limited to the specific device shown.

What I claim is l. The method of depolarizing the elec' trodes of electrolytic rectifiers and similar apparatus by the removal of bubbles therefrom, which consists in displacing an electrolyte from the vessel containing the electrot es by the accumulation therein of a gas under pressure and periodically liberating and discharging the accumulated gas to permit the return of the electrolyte. as set forth.

2. The method of depolarizing the electrodes'of electrolytic rectifiers and similar apparatus by the removal of bubbles therefrom, which consists in displacing an electrolyte from the vessel containing the electrodes by the accumulation therein of a gas under pressure, and effecting by the pressure of a given volume of such gas the periodic liberation and discharge of the same, to permit the return of the electrolyte. as set forth.

3. The herein described method of depolarizing the electrodes of electrolytic recti fiers and similar apparatus by the removal of bubbles therefrom, which consists in alternately exposing the electrodes to a gaseous medium and bring about rcsubmergcnco of the electrodes in an electrolyte.

t. The combination with a closed chamber, an electrolyte in said chamber, and an electrode immersed in the electrolyte in said chamber, of a vessel intowhich the electrolyte displaced by the accumulation of gas in the electrode chamber flows, and means for permitting the escape of the confined gas intermittently, and thereby Jermitting the return to the electrode cham er of the displaced electrolyte, as set forth.

5. An electrolytic apparatus comprising in combination an open chamber, a closed chamber connected therewith, electrodes contained in both of said chambers, an electrolyte, and a gas discharge valve operated by the pressure of a iven volume of gas confined in the closed chamber, whereby electrolyte displaced from the closed to the open chamber by the accumulation of such gas will be intermittently returned to the closed chamber, as set forth.

(3. An electrolytic apparatus comprisin in combination, an open chamber, a ClOS( chamber communicating therewith, electrodes contained in both of said chambers, an electrolyte, and means for compensating for the displacement of electrolyte from one chamber to the other so that the area of active electrode surface is preserved constant, as set forth.

7. In an electrolytic apparatus the combination of an electrolyte, an open electrode chamber and a closed electrode chamber ccmnmnicating therewith and shaped or formed so that the generation of gas therein by electrolytic action displacing the electrolyte and forcing it into the open chamber will lower the level of such electrolyte at a uniform rate, as set forth.

8. In an electrolytic a paratus, the combination of an open chum )er, a closed chamber, electrodes in both of said chambers, an electrolyte, passages of communication between said chambers whereby the development of gas in the closed chamber will expel electrolyte therefrom into the open chamber and the escape of the confined gas will permit the return of the electrolyte, and means for causim the circulation. produced by expulsion of electrolyte from the closed chamber to maintain the direction of movement incident to the circulation prodneed by convection in the electrolyte, as set forth.

9. The combination of a vessel, :1 closed electrode chamber conununicating at its lower end with said vessel, an electrolyte in the closed chamber, electrodes immersed in the electrolyte in the closed chamber, and a U-tube extending from the closed chamber .into said vessel and constituting an automatic valve for the periodic escape of the gas generated in the closed chamber, as set forth.

10. The combination with an open containing vessel, of a closed vessel, an electrolyte, connecting pipes or tubes between the lower portirn of said vessels whereby electrolyte displaced from the closed vessel will ilow into the open vessel and return by gravity when the displacing pressure is relieved, electrodes immersed in the electrolyte contained in said vessels and a U-tube one leg of which extends from the closed into the open vessel to constitute an automatic valve for the periodic escape of gas gene 'ated in the closed vessel, as set forth.

11. The combination of acontaining vessel, an electrolyte therein, an electrode normally immersed in the electrolyte, and means for intermittently causin exposure of the normally submerged surface of the electrode to a gaseous medium.

12. The combination of an electrolyte, electrodes normally immersed in the electrolyte, and means for intermittently and alternately exposing the normally submerged surfaces of the electrodes to a gaseous medium.

13. The combination of an electrolyte, electrodes adapted for subm ergcnce therein, and means for intermittently causing progressive exposure of one electrode to a gaseous medium and progressive submergence of the other, whereby the total submerged electrode-surface is maintained substantially constant.

In testimony whereof I ailix my signature in the presence of two subscribing wit- S. S. DUNIIAM.

Copies oi. this patent may be obtained (or five cents each, by addressing the "Commissioner of Patents, Washington, D. 0. 

